It’s safe to say that among both hardcore and casual fans of movies made from comic books, the “X-Men” series has gotten some of the highest accolades. It’s been, for the most part, a classy bunch of films featuring a generous helping of fascinating characters. The sole entry that didn’t quite hit the mark was “X-Men: The Last Stand.” That was also the only film in the series that didn’t have the stamp of producer-director Bryan Singer. Singer only produced 2011’s “X-Men: First Class,” but that film was under the capable direction of Matthew Vaughn. Singer returns to full-fledged producer-director status with “Days of Future Past,” and he’s made the best of these films to date.

The only warning to be dealt out in advance is that the opening frames greet viewers with pandemonium, with non-stop action that takes a while to make sense of but eventually becomes clear when the pace slows down enough to let the storytelling begin. As happens so many times in a successful franchise, this film is going to be much easier to follow for those who have been watching the series from the start. In fact, even though care has been taken to satisfactorily explain what’s going on, some pieces of this one will be distracting to newcomers. You might want to first check out “X-Men: First Class,” which introduces the cast of actors who play the younger versions of X-Men heroes and villains Charles Xavier, Erik Lehnsherr and Raven/Mystique.

One of the best things about “Days of Future Past” (aside from the non-Moody Blues-related title) is that the film manages to mix the older and younger casts together in a story that puts time travel at its center and actually manages to pull it off. Time travel has long been a genre writers have freely played with and changed the rules of as they went along. Here, along with some additional but temporary confusion, it works.

At the film’s start, things are going badly for the whole world. The longtime war between humans and mutants has turned far more vicious than either side had expected. The humans have created an army of creatures called Sentinels – tall, sleek humanoid things that are fast and destructive and seemingly indestructible, whose only purpose is to hunt down and eliminate all mutants.

They’ve been quite adept at their task, and the remaining mutants, including the current-day versions of the characters who originated the roles (Patrick Stewart, Ian McKellen, Hugh Jackman, et al), know they’re in trouble. With the help of more recent mutant additions (notably Ellen Page), they devise a plan to change history, to prevent the invention of the Sentinels, by sending one of their own back in time in order to … .

Page 2 of 2 - No, that won’t be given away here. What will be revealed is that only the mind of the time traveling mutant will go back to 1973, the year of a certain fate-changing event, and that mind will become one with the mutant’s own younger body. The only member strong enough to take on this taxing challenge is Wolverine (Jackman), who never ages and whose body has remarkable healing powers. It’s another nice touch having Hugh Jackman play Wolverine both now and then, going back to meet the other younger mutants, played in the past by James McAvoy, Michael Fassbender and Jennifer Lawrence (whose character of Raven/Mystique is not seen in the present).

Hmmm, this does sound confusing, doesn’t it? And there hasn’t even been mention made yet of single-minded mutant-hating Dr. Bolivar Trask (the excellent Peter Dinklage) or the fact that the film’s plot neatly factors in a touch of JFK assassination theory.

Not to worry, all does come clear under the sure control of Singer and writer Simon Kinberg. When it’s time for action, it’s let loose. When the story could use a good laugh, it’s provided (especially in a scene where the young mutant named Peter, aka Quicksilver (Evan Peters), makes things laugh-out-loud-worthy by besting a group of armed military guards in slapstick fashion).

The film also has its serious dramatic sides, during which it focuses on personal relationships, philosophical ideas and historical incidents. But no front seat is taken by drama or action or comedy, and the mix of all three is what makes the film work so well. There’s also a terrific ending that will please longtime followers, and a post-credits ending that introduces the series’ next menacing villain. Hint: That second ending also offers a hint of how the pyramids were built.